Characterization and physicochemical studies of the conjugates of graphene quantum dots with differently charged zinc phthalocyanines

Refilwe Matshitse; Kutloano E. Sekhosana; Ojodomo J. Achadu; Tebello Nyokong

doi:10.1080/00958972.2017.1387652

Characterization and physicochemical studies of the conjugates of graphene quantum dots with differently charged zinc phthalocyanines

Refilwe Matshitse, Kutloano E. Sekhosana, Ojodomo J. Achadu, Tebello Nyokong

SHLS Life Sciences

Research output: Contribution to journal › Article › peer-review

12 Citations (Scopus)

Abstract

Unsubstituted zinc phthalocyanine (ZnPc), 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ) and Zn tetrasulfo phthalocyanine (ZnTSPc) were non-covalently (electrostatic and/or π–π interaction) attached to graphene quantum dots (GQDs) to form GQDs-Pc nanoconjugates. Relative to Pcs alone, the presence of GQDs improved the triplet quantum yields with the following values: GQDs-ZnPc (0.73), GQDs-ZnTPPcQ (0.76) and GQDs-ZnTSPc (0.67). Respective Förster resonance energy transfer (FRET) efficiencies were calculated to be 0.81, 0.80 and 0.28. However, singlet oxygen generating abilities of the as-synthesized nanoconjugates were relatively low due to the screening effect of GQDs and quenching in water. This study shows that, the type of Pc, loading and solvent used are among the vital properties to consider when constructing GQD-nanoconjugate systems with optimal triplet quantum yield properties and investigation of their physicochemical properties.

Original language	English
Pages (from-to)	3308-3324
Number of pages	17
Journal	Journal of Coordination Chemistry
Volume	70
Issue number	19
DOIs	https://doi.org/10.1080/00958972.2017.1387652
Publication status	Published - 26 Oct 2017

Bibliographical note

Funding Information:
This work was supported by the Department of Science andTechnology (DST), Innovation and National Research Foundation (NRF), South Africa through DST/NRF South African Research Chairs Initiative for Professor of Medicinal Chemistry and Nanotechnology (UID 62620), as well as Rhodes University.

Publisher Copyright:
© 2017 Informa UK Limited, trading as Taylor & Francis Group.

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title = "Characterization and physicochemical studies of the conjugates of graphene quantum dots with differently charged zinc phthalocyanines",

abstract = "Unsubstituted zinc phthalocyanine (ZnPc), 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ) and Zn tetrasulfo phthalocyanine (ZnTSPc) were non-covalently (electrostatic and/or π–π interaction) attached to graphene quantum dots (GQDs) to form GQDs-Pc nanoconjugates. Relative to Pcs alone, the presence of GQDs improved the triplet quantum yields with the following values: GQDs-ZnPc (0.73), GQDs-ZnTPPcQ (0.76) and GQDs-ZnTSPc (0.67). Respective F{\"o}rster resonance energy transfer (FRET) efficiencies were calculated to be 0.81, 0.80 and 0.28. However, singlet oxygen generating abilities of the as-synthesized nanoconjugates were relatively low due to the screening effect of GQDs and quenching in water. This study shows that, the type of Pc, loading and solvent used are among the vital properties to consider when constructing GQD-nanoconjugate systems with optimal triplet quantum yield properties and investigation of their physicochemical properties.",

author = "Refilwe Matshitse and Sekhosana, {Kutloano E.} and Achadu, {Ojodomo J.} and Tebello Nyokong",

note = "Funding Information: This work was supported by the Department of Science andTechnology (DST), Innovation and National Research Foundation (NRF), South Africa through DST/NRF South African Research Chairs Initiative for Professor of Medicinal Chemistry and Nanotechnology (UID 62620), as well as Rhodes University. Publisher Copyright: {\textcopyright} 2017 Informa UK Limited, trading as Taylor & Francis Group.",

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doi = "10.1080/00958972.2017.1387652",

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AU - Matshitse, Refilwe

AU - Sekhosana, Kutloano E.

AU - Achadu, Ojodomo J.

AU - Nyokong, Tebello

N1 - Funding Information: This work was supported by the Department of Science andTechnology (DST), Innovation and National Research Foundation (NRF), South Africa through DST/NRF South African Research Chairs Initiative for Professor of Medicinal Chemistry and Nanotechnology (UID 62620), as well as Rhodes University. Publisher Copyright: © 2017 Informa UK Limited, trading as Taylor & Francis Group.

PY - 2017/10/26

Y1 - 2017/10/26

N2 - Unsubstituted zinc phthalocyanine (ZnPc), 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ) and Zn tetrasulfo phthalocyanine (ZnTSPc) were non-covalently (electrostatic and/or π–π interaction) attached to graphene quantum dots (GQDs) to form GQDs-Pc nanoconjugates. Relative to Pcs alone, the presence of GQDs improved the triplet quantum yields with the following values: GQDs-ZnPc (0.73), GQDs-ZnTPPcQ (0.76) and GQDs-ZnTSPc (0.67). Respective Förster resonance energy transfer (FRET) efficiencies were calculated to be 0.81, 0.80 and 0.28. However, singlet oxygen generating abilities of the as-synthesized nanoconjugates were relatively low due to the screening effect of GQDs and quenching in water. This study shows that, the type of Pc, loading and solvent used are among the vital properties to consider when constructing GQD-nanoconjugate systems with optimal triplet quantum yield properties and investigation of their physicochemical properties.

AB - Unsubstituted zinc phthalocyanine (ZnPc), 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ) and Zn tetrasulfo phthalocyanine (ZnTSPc) were non-covalently (electrostatic and/or π–π interaction) attached to graphene quantum dots (GQDs) to form GQDs-Pc nanoconjugates. Relative to Pcs alone, the presence of GQDs improved the triplet quantum yields with the following values: GQDs-ZnPc (0.73), GQDs-ZnTPPcQ (0.76) and GQDs-ZnTSPc (0.67). Respective Förster resonance energy transfer (FRET) efficiencies were calculated to be 0.81, 0.80 and 0.28. However, singlet oxygen generating abilities of the as-synthesized nanoconjugates were relatively low due to the screening effect of GQDs and quenching in water. This study shows that, the type of Pc, loading and solvent used are among the vital properties to consider when constructing GQD-nanoconjugate systems with optimal triplet quantum yield properties and investigation of their physicochemical properties.

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Characterization and physicochemical studies of the conjugates of graphene quantum dots with differently charged zinc phthalocyanines

Abstract

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